The present invention relates generally to the field of surgery and more particularly to surgery directed to the repair of injuries or defects, usually considered plastic and reconstructive surgery of the human body.
In the practice of plastic and reconstructive surgery, it is often necessary to employ the use of tissue or foreign materials to provide a means to fill in defects which may be present in the human body. One such defect which occurs is enophthalmus wherein one eyeball cannot be coordinated with the other due to differences in the volume of the orbital contents which may have been created by either trauma or developmental anomaly. Such a volume defect prevents coordination of binocular vision, interferes with appropriate opening and closing of defective eyelids, and adversely affects appearance.
Another exemplary defect is an uneven vermillion border that is the result of a laceration, or from a cleft lip surgical repair. During the initial opposition of the separated tissues, there is tension and resultant loss of three dimensional symmetry of structure. By increasing the volume of the lip, three dimensional symmetry of structure is restored and the vermillion border is not disrupted. Paralysis or ablution of the vocal cords causing aphonia or dysphonia may be corrected by such augmentation. Traumatic or surgically altered bones, skin and subcutaneous tissue often have similar defects that interfere with form, function, or both.
In the practice of plastic and reconstructive surgery, inert materials have frequently been implanted to fill these defects. Recently, various collagen compounds and fibrin matrices have been injected to fill these defects. Bioactive materials such as hydroxyapatite or cordal granules (osteo conductive) have been used for hard tissue defects. Another prior art technique is to use adjacent or distant autologous tissues. Also, but on a rare or infrequent basis, cadaver and other species tissues have been used for fill-in substances. Liquid silicone has been used in the past as an injectable substance for very small defects. Although some scar tissue forms around the silicone liquid droplets, it is subject to rampant and distant migration throughout the body and the ultimate location for such substances tends to be unpredictable. As a result, liquid silicone has generally been viewed as a dangerous substance by most plastic surgeons. Although it has been useful in controlled studies in very small (one-tenth of a cc. to 1 cc.) injections, it is currently not approved for general use because of its tendency to migrate.
While it has been suggested to compound certain very small particle species in a lubricious material and to inject such combination micro particle media subcutaneously for both soft and hard tissue augmentation, heretofore success has been limited. Undesirable subsequent particle migration and serious granulomatous reactions commonly resulted. This is well documented with such materials as polytetrafluoroethylene spheres of very small diameter (&gt;90% of a diameter .ltoreq.30 microns) in glycerine. See, for example, Malizia, et al., JAMA, Volume 251, No. 24, pp. 3277-3281 (1984), as a typical commentary or evaluation. The use of very small diameter particulate spheres (approximately 1-20 microns) or small diameter elongated fibrils, (generally 1-30 microns in diameter) of various materials such as cross-linked collagen in a biocompatible fluid lubricant as injectable implant compositions are disclosed in U.S. Pat. No. 4,803,075. While these materials create immediate augmentation, they also have a tendency to migrate and/or be reabsorbed from the injection site.
In accordance with the present invention, very small particles or micro particles and, in particular, textured micro particles are employed as an injectable solid substance for use in reconstructive surgical procedures. Textured micro particles having an outside diameter of between about 30 and 3000 microns (or between approximately 0.003 and 0.3 cm.) may be injected into the body along with an appropriate physiologic vehicle to enable the filling of defects. Accordingly, and in accordance with the present invention, textured micro particles to be described in more detail hereinafter may be employed which are fabricated from an elastomer such as silicone, an inert material such as polytetrafluoroethylene (Teflon), bioactive materials such as hydroxyapatite, ceramics or other inert substances. These textured micro particles may be introduced and placed at a precise location, and because of the textured configuration, tissue ingrowth will prevent dislodgement and ultimate migration. Furthermore, any over-correction can be readily adjusted by use of blunt cannulas and suction which provides for safe removal.